HP200A
Encyclopedia
The HP200A was the first product made by Hewlett-Packard
and was manufactured in David Packard
's garage in Palo Alto, California
.
It was a low-distortion audio oscillator used for testing sound equipment. It used the Wien bridge oscillator
circuit, which had been the subject of Bill Hewlett's Masters thesis. It was also the first such commercial oscillator to use a simple light bulb as the temperature-dependent thermistor
in its feedback network. Using a positive temperature coefficient (PTC) thermistor is a key technique for achieving low distortion with a Wien bridge. Hewlett's innovation of using a light bulb as such was a cheap and effective alternative. Its filament also had a lower thermal mass than other available thermistors, allowing operation down to lower frequencies.
The product code was chosen to give the impression that HP was an established company. Walt Disney
bought eight of them for use in the production of Fantasia
.
The circuit diagram is shown in a US patent Hewlett filed July 11, 1939, granted January 6, 1942
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...
and was manufactured in David Packard
David Packard
David Packard was a co-founder of Hewlett-Packard , serving as president , CEO , and Chairman of the Board . He served as U.S. Deputy Secretary of Defense from 1969–1971 during the Nixon administration...
's garage in Palo Alto, California
Palo Alto, California
Palo Alto is a California charter city located in the northwest corner of Santa Clara County, in the San Francisco Bay Area of California, United States. The city shares its borders with East Palo Alto, Mountain View, Los Altos, Los Altos Hills, Stanford, Portola Valley, and Menlo Park. It is...
.
It was a low-distortion audio oscillator used for testing sound equipment. It used the Wien bridge oscillator
Wien bridge oscillator
A Wien bridge oscillator is a type of electronic oscillator that generates sine waves. It can generate a large range of frequencies. The oscillator is based on a bridge circuit originally developed by Max Wien in 1891....
circuit, which had been the subject of Bill Hewlett's Masters thesis. It was also the first such commercial oscillator to use a simple light bulb as the temperature-dependent thermistor
Thermistor
A thermistor is a type of resistor whose resistance varies significantly with temperature, more so than in standard resistors. The word is a portmanteau of thermal and resistor...
in its feedback network. Using a positive temperature coefficient (PTC) thermistor is a key technique for achieving low distortion with a Wien bridge. Hewlett's innovation of using a light bulb as such was a cheap and effective alternative. Its filament also had a lower thermal mass than other available thermistors, allowing operation down to lower frequencies.
The product code was chosen to give the impression that HP was an established company. Walt Disney
Walt Disney
Walter Elias "Walt" Disney was an American film producer, director, screenwriter, voice actor, animator, entrepreneur, entertainer, international icon, and philanthropist, well-known for his influence in the field of entertainment during the 20th century. Along with his brother Roy O...
bought eight of them for use in the production of Fantasia
Fantasia (film)
Fantasia is a 1940 American animated film produced by Walt Disney and released by Walt Disney Productions. The third feature in the Walt Disney Animated Classics series, the film consists of eight animated segments set to pieces of classical music conducted by Leopold Stokowski, seven of which are...
.
The circuit diagram is shown in a US patent Hewlett filed July 11, 1939, granted January 6, 1942